In any manufacturing process, it is desirable to perform some tests on a device before it can be certified as being in acceptable condition for use. For example, in a communications device it is important to test whether it can successfully send data to and receive data from a remote device. It may also be desirable to configure the device during manufacturing to set any variable parameters to ones that are proper for operational use. In a communications device this could include setting channels that are used, codes that are used, power levels, etc.
When performing this testing, configuration, and calibration, it is generally desirable to have a communication link between testing equipment and the device to be tested. This link can be used to pass testing or configuration instructions from the testing equipment to the device to be tested, or to pass some kind of acknowledgement of those instructions from the device to be tested to the testing equipment.
Devices have typically been provided with a dedicated testing link that is used during the testing, calibration, and configuration process. The connections for this link can then be sealed off after testing is complete, severely limiting a users ability to access it after purchase. This provide a relatively secure link for testing, but also increases the complexity, size, and cost of the final device.
Communications devices have an existing communications link, but this has not been considered a viable testing link because its use could open up a huge security gap, allowing the device to be improperly reconfigured or otherwise compromised in the future. In other words, if a testing device could connect up to the device under testing during a testing, configuration, and calibration process and perform testing, configuration, and calibration operations, then another device might be able to do so at a later time, long after testing, configuration, and calibration was completed. This is of particular concern when the basic communications link is used (as opposed to a dedicated testing link) because that basic communications link will remain in use during the life of the device.
And if the testing, configuration, and calibration operations were improperly accessed, the device could be reconfigured in ways that might be improper or even illegal. For example, an unscrupulous user might use the communications link to change the codes used, to change the frequency used, to increase the transmission power beyond regulatory limits, etc.
It is therefore desirable to provide a means by which a communication device's basic communications link can be used for testing a device, but in a manner that will not open it up to later security vulnerabilities.